This invention relates to an alloy powder having hard particles dispersed therein and a method of manufacturing the alloy powder. The alloy powder may be used as a magnetic grinder material, a material for cladding and strengthening the surface of a parent material by welding the alloy powder onto the surface (hereinafter referred to the cladding material), or for other purposes.
In known alloy powders with hard particles dispersed therein, the hard particles are dissolved and coagulated in a metal matrix.
Conventionally, when the alloy powder is manufactured, a hard particle powder and a metal particle powder are first blended to form a mixture material. The mixture material is then welded to form a welded bead on a water-cooled copper plate or other metal surface. Lastly, the welded bead is mechanically ground into powder, and the powder is classified.
The particle diameter of the mixture material to be welded is required to be regulated between 30.mu. (microns) and 300.mu. (microns), preferably between 50.mu. and 300.mu., such that the mixture material can be appropriately supplied through air injection for a subsequent welding step. Therefore, the hard particle powder and the metal particle powder originally have a particle diameter regulated within the specified ranges. Since the hard particles carried in the welded bead also have a large diameter, it takes a long period of time to mechanically grind the welded bead because of resistance from the hard particles. Further, the hard particles, which are more brittle as compared with base metal particles, are ground prior to the base metal particles and thus, easily drop therefrom. Consequently, the hard particles are dispersed inconsistently in the manufactured alloy powder. The hard particles, even if prevented from dropping from the base metal particles, are incompletely dissolved and coagulated because of their large particle diameter, and therefore they fail to be uniformly dispersed in the alloy powder. The hard particles carried in the alloy powder are so large that they are inappropriate as the grinder material for finishing a specular surface or surfaces of other precision instruments.